Major Antarctic ice sheet shrank when it wasn’t much warmer than now

Ars Technica » Scientific Method 2018-09-20

View of a glacier meeting the ocean.

Enlarge (credit: NASA)

Are the big ice sheets in Antarctica stable in the face of the warming we've already committed to? That's a more serious question than it might sound. The continent is thought to hold enough ice to raise ocean levels by over 55 meters if it were to melt—enough to drown every single bit of coastal infrastructure we have and send people migrating far inland from the present-day shoreline.

But the melting of this ice is a complicated process, one that depends on things like the dynamics of glaciers as they push through coastal hills, the shape of the seafloor where the ice meets it, and the slope of the basins the ice sheets sit in. It's tough to reason out how much ice would be lost for a given bit of warming. As a result, we're left with historical comparisons—the last time it warmed by that amount, how much ice did we lose?

This week, we got some new information on this topic courtesy of a detailed study of Antarctica's Wilkes Subglacial Basin. The work showed that it wasn't so much the amount of warming the ice experienced; it was how long it stayed warm.

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